Air handling systems are commonly fitted with filters that remove chemical and particulate hazards from the air supply. Such systems can be used in a variety of situations including protection within buildings and on mobile locations such as ships. Filters commonly used for collective protection air handling systems are often cylindrically shaped and have an inlet at the inner surface of the filter housing. The outlet of such filters is typically located at the outermost periphery of the filter. Such filters typically have a pleated particulate filter section intended to target particulate contaminants that is disposed near the inlet of the filter. They also often have a chemical filter bed that targets gases. Known filter beds include packed filter beds, and bonded particle masses. Filter beds may include multiple layers. The chemical and particulate filter elements within the filter system may be contained as layers in a single filter element or deployed as separate filter elements.
Many filters are disposable. When known filters require replacement, either the entire unit including the housing is discarded and replaced or the individual cartridge is removed from the housing and then discarded and replaced. There exists a need for improved filter systems that are less expensive and create less waste.